/*
 * Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 */

package java.security.cert;

import java.io.Serializable;
import java.util.Collection;
import java.util.Collections;

/**
 * Parameters used as input for the Collection {@code CertStore}
 * algorithm.
 * <p>
 * This class is used to provide necessary configuration parameters
 * to implementations of the Collection {@code CertStore}
 * algorithm. The only parameter included in this class is the
 * {@code Collection} from which the {@code CertStore} will
 * retrieve certificates and CRLs.
 * <p>
 * <b>Concurrent Access</b>
 * <p>
 * Unless otherwise specified, the methods defined in this class are not
 * thread-safe. Multiple threads that need to access a single
 * object concurrently should synchronize amongst themselves and
 * provide the necessary locking. Multiple threads each manipulating
 * separate objects need not synchronize.
 *
 * @author Steve Hanna
 * @see java.util.Collection
 * @see CertStore
 * @since 1.4
 */
public class CollectionCertStoreParameters
    implements CertStoreParameters {

  private Collection<?> coll;

  /**
   * Creates an instance of {@code CollectionCertStoreParameters}
   * which will allow certificates and CRLs to be retrieved from the
   * specified {@code Collection}. If the specified
   * {@code Collection} contains an object that is not a
   * {@code Certificate} or {@code CRL}, that object will be
   * ignored by the Collection {@code CertStore}.
   * <p>
   * The {@code Collection} is <b>not</b> copied. Instead, a
   * reference is used. This allows the caller to subsequently add or
   * remove {@code Certificates} or {@code CRL}s from the
   * {@code Collection}, thus changing the set of
   * {@code Certificates} or {@code CRL}s available to the
   * Collection {@code CertStore}. The Collection {@code CertStore}
   * will not modify the contents of the {@code Collection}.
   * <p>
   * If the {@code Collection} will be modified by one thread while
   * another thread is calling a method of a Collection {@code CertStore}
   * that has been initialized with this {@code Collection}, the
   * {@code Collection} must have fail-fast iterators.
   *
   * @param collection a {@code Collection} of {@code Certificate}s and {@code CRL}s
   * @throws NullPointerException if {@code collection} is {@code null}
   */
  public CollectionCertStoreParameters(Collection<?> collection) {
    if (collection == null) {
      throw new NullPointerException();
    }
    coll = collection;
  }

  /**
   * Creates an instance of {@code CollectionCertStoreParameters} with
   * the default parameter values (an empty and immutable
   * {@code Collection}).
   */
  public CollectionCertStoreParameters() {
    coll = Collections.EMPTY_SET;
  }

  /**
   * Returns the {@code Collection} from which {@code Certificate}s
   * and {@code CRL}s are retrieved. This is <b>not</b> a copy of the
   * {@code Collection}, it is a reference. This allows the caller to
   * subsequently add or remove {@code Certificates} or
   * {@code CRL}s from the {@code Collection}.
   *
   * @return the {@code Collection} (never null)
   */
  public Collection<?> getCollection() {
    return coll;
  }

  /**
   * Returns a copy of this object. Note that only a reference to the
   * {@code Collection} is copied, and not the contents.
   *
   * @return the copy
   */
  public Object clone() {
    try {
      return super.clone();
    } catch (CloneNotSupportedException e) {
            /* Cannot happen */
      throw new InternalError(e.toString(), e);
    }
  }

  /**
   * Returns a formatted string describing the parameters.
   *
   * @return a formatted string describing the parameters
   */
  public String toString() {
    StringBuffer sb = new StringBuffer();
    sb.append("CollectionCertStoreParameters: [\n");
    sb.append("  collection: " + coll + "\n");
    sb.append("]");
    return sb.toString();
  }
}
